Damage of E.coli cell membrane and intracellular enzymic activity induced by pulsed light irradiation

After pulsed light treatment on the suspension of E.coli in logarithmic growth phase,research the change of cell membrane permeability and intracellular enzymic activity.The result indicated that protein leakage and MDA formation increased with the decline of the survival rate of E.coli.Through pilot studies,drawn input voltage to 1 500 V,flash as 32times,the leakage of protein was 13.03μg/mL and the formation amount of MDA was 2.76nmol/L.NaCl tolerance was obviously lower than the control group(P 0.01).In addition,intracellular enzymic activity lower than untreated,SOD was decreased to 83.78%as well as CAT was decreased to 76.92%.Therefore,the damage of cell barrier structure caused the change of osmotic pressure and cell membranes permeability.It can change intracellular bacterial substances even it caused cell died.It would be certain meaning that synergistic reaction which hydroxyl radicals acted on lethality cell.